This application claims the priority of German Patent Document 199 39 528.4, filed Aug. 20, 1999, the disclosure of which is expressly incorporated by reference herein.
The invention relates to an electrical rotating machine having a rotor and a stator, the rotor and the stator each comprising bundles of laminations positioned by way of separate carrying elements (rotor hub, stator housing), and a non-rotatable connection being achieved between the respective carrying element and the assigned bundle of laminations by a form-locking contact of the carrying element on the pertaining bundle of laminations which is caused by plastic deformation.
For fastening iron lamina on a rotor bush of an electrical rotating machine, it is known from the type-forming German Patent Document DE-PS 292 175 that, from the inside, the iron bush is so far expanded that it penetrates slightly between the individual lamination and holds them separate from one another. As a result, the wall of the rotor bush comes in intimate contact with the respective inner bore of the individual lamination so that a subsequent displacement is excluded. In this case, the material of the bush penetrates between the individual lamination and keeps them separate from one another.
A disadvantage of this known non-rotatable connection achieved by plastic deformation is the operationally unreliable absorption and transmission of high torques.
It is an object of the invention to indicate a simple further development in combination with an effective deformation process for the non-rotatable connection between the respective bundle of laminations and the pertaining carrying element of an electrical rotating machine for the reliable transmission of high torques.
This object is achieved in that the respective bundle of laminations has a profiled contact surface for the assigned carrying element, and in that, by an electromagnetic forming of the carrying element (hub) effective at least in areas, its form-locking contact is achieved on the profiled contact surface of the bundle of laminations.
By means of the invention, a highly stressable, non-rotatable connection is created in a particularly advantageous manner.
In the case of a rotor having a bundle of laminations with longitudinal grooves, a further development advantageous with respect to the fatigue strength is achieved in that the contact surface for the rotor hub has a wave profile, a surface-enlarging wave crest being assigned to each longitudinal groove.
By means of this further development, in addition to a mechanically highly stressable connection, an undisturbed course of the magnetic field lines around the longitudinal grooves is also achieved during use of the machine.
For an electrical rotating machine having a rotor of a low flywheel effect (GD2), according to the invention, the rotor hub is constructed with a relatively thin-walled cylinder jacket which is molded into the wave profile of the bundle of laminations by means of electromagnetic formation.
For an electrical rotating machine having a rotor of a higher flywheel effect and/or a higher torque transmission, it is suggested that the rotor hub in the cast construction have a connection surface corresponding to the wave profile of the bundle of laminations, and that the shrinkage occurring with the cooling of the cast hub results in a joining play used for joining the cast hub with the bundle of laminations, which is eliminated after the joining by electromagnetic forming.
By means of this further development, a simplified manufacturing is achieved at reasonable cost, in which case the cast rotor hub, depending on the requirements, for reasons of acoustics and/or ventilation, may have a cylindrical or profiled design on the interior side.
Another aspect of the invention relates to the fact that an additional indentation is provided in the profiled contact surface of the respective bundle of laminations, a section of the rotor hub molded into the indentation by means of electromagnetic formation being used for the axial securing of the rotor hub relative to the bundle of laminations.
Thus, in addition to the torque transmission in the circumferential direction secured by the wave profile, an axial securing of the rotor is also achieved relative to its bundle of laminations.
The electrical rotating machine designed according to the invention is preferably used as an asynchronous motor, as a starter and generator device, which can be coupled to a crankshaft of an internal-combustion engine.
In the case of a stator which encloses the rotor in a conventional manner, the bundle of laminations of the stator, in the manner according to the invention, can be in a non-rotatable connection, for example, with a housing bell connecting the internal-combustion engine and the adjoining transmission, the housing bell being connected by means of electromagnetic forming with the bundle of laminations of the stator by plastic deformation.
Reference is made to the following publications for background information on electromagnetic forming:
(1) U.S. Pat. No. 3,541,823
(2) U.S. Pat. No. 3,810,372
(3) U.S. Pat. No. 5,331,832
(4) U.S. Pat. No. 5,457,977
(5) U.S. Pat. No. 5,586,460
(6) Article titled xe2x80x9cElectromagnetic Metalformingxe2x80x9d, February 1978 issue of Manufacturing Engineers.